1. Field of the Invention
The invention disclosed herein pertains to polymeric compositions containing a flame retarding amount of a substituted s-triazine compound.
2. Description of the Prior Art
During the past several years, a large number of flame retardants have been developed for use with an almost equally large number of flammable materials. Cellulosic materials such as paper and wood, and polymeric materials such as synthetic fibers and bulkier plastic articles are just two examples of the materials for which flame retardants have been developed. For any class of flammable materials, such as synthetic high polymers, those skilled in the art have long been aware that some flame retardant additives are more effective in polymers and polymeric compositions than other flame retardant additives. This is because the efficacy of any flame retardant in polymers or polymeric compositions is measured not only by the flame retarding capability of the additive but also by the ability of the additive to improve or modify, or at least not to detract from, other physical or mechanical properties of the polymer or polymeric composition. The mere fact, therefore, that most flame retardants contain halogen, phosphorus, and/or nitrogen atoms does not assure that any given halogenated or phosphorus or nitrogen-containing compound will impart useful flame retarding characteristics to all or even to any polymeric systems. Furthermore, as those skilled in the art have improved the flame retardancy of many polymeric materials, they have been simultaneously required to provide the necessary flame retardancy with a minimal effect upon other properties of the polymers such as their light stability, processability and flexural, tensile and impact strengths. Balancing all of the foregoing considerations and thereby developing polymeric compositions with good flame retardant characteristics as well as a satisfactory balance of other properties is, consequently, a task which has in the past and presently continues to require the exercise of a high degree of inventive skill.
In contrast to the present invention which lies within the art of flame retardants, Br. Pat. No. 1,215,286 discloses an intumescent paint composed of melamine hydrobromide, a zinc oxide fluxing agent, and an epoxide resin. Although both the flame retardant art and the intumescent art have as their ultimate aim a reduction of the hazards associated with fires and combustion, said arts approach their objective through divergent techniques because of the different theories and mechanisms under which they operate. Because of these fundamental differences between the two arts, one skilled in the art of flame retardants recognizes that one cannot indiscriminately take an intumescent composition and expect it to possess flame retardant efficacy when incorporated into, as opposed to being applied onto, a polymeric substrate. A great degree of inventive skill is required to successfully affect such a transposition.